Bahtinov mask question?

[Skipper Billy]

Is the distance between the Bahtinov mask and the front of the scope critical ?

I usually use it perched on the built in dew shield of my ED80 but wondered if it would work as well perched on the end of my home made camping mat dew shield some 5" further away from the front of the scope ??

Would it make any difference??

[steppenwolf]

I have found Bahtinov masks to be very resilient to all sorts of spacing configurations although I do try hard to have them centred over the optics as closely as possible. I don't think you will have any problem with it attached to the end of your extended dew shield.

[bobmoss]

I don't think the distance matters at all - I've never seen it mentioned in instructions that it should be a certain distance away.

[rwg]

Moving the mask away from the lens to the end of the dew shield will have the very minor effect of making the spikes a little longer and fainter (because the light will be more spread out over the length). The focus accuracy isn't affected.

cheers,

Robin

[Skipper Billy]

Thanks very much - something else I can scratch off my "astroworry" list !! ;-)